Minimum-invasive treatment are effective therapy methods that place less physical burden on patients and allow reductions in medical treatments after a surgery and in rehabilitation period. As methods of minimum-invasive percutaneous treatment, local therapies in which a puncture needle is directly led to a tumor tissue in an organ to necrotize the tumor tissue by a radio wave, microwave, laser, or the like have been attracting attention. There is also known a puncture system in which a puncture needle is inserted to a skin while a position of a tumor is confirmed by equipment such as ultrasound, CT, or MRI so as to allow confirmation that the needle has reached inside the tumor.
In a puncture control system, it is required that a tip of the puncture needle accurately reach a puncture target position (for example, tumor tissue) in a tissue of an organ. However, a puncture operation requires skill and trial and error of a doctor because a puncture error is generated, and is difficult even with image guidance. The puncture error includes, for example, a target trajectory error and a target displacement error.
The target trajectory error is an error in which the puncture needle itself deforms with a resistance while traveling through the tissue of the organ, and because the deformation is not uniform due to unevenness of the tissue in a puncture route, a direction of travel of the needle is displaced. The target displacement error is an error that is generated because a target position is moved when, while the needle travels through the tissue of the organ, the tissue of the organ is deformed by a force imparted to the organ by the needle or the tissue is deformed with a change in direction of gravitational force with respect to a posture of the patient.
Such puncture error leads to a problem in that the tip of the puncture needle does not accurately reach the puncture target position in the tissue of the organ, or in which the route through which the needle reaches the puncture target position greatly differs from a planned route because the puncture target position is moved.
In the conventional puncture control system, the puncture error in which the puncture target position is displaced when, while correcting a course of the needle, the force of the tip of the needle is transferred to the puncture target position through the tissue of the organ has not been considered. Therefore, there are known a system and a method in which the course correction is performed every time the puncture target position is displaced.
PTL 1 discloses a puncture control system for correcting various kinds of information (general information) of the general human liver to individual information corresponding to the individual difference of a puncture object patient. The puncture control system combines information by a model obtained from the individual information with force information and visual information obtained by a force sensor and an image acquisition device to decide a course of a needle, and gives a drive command to an actuator.